In general, power generated from an internal combustion engine burns fuel within a cylinder to generate a high pressure in the cylinder, wherein the power is obtained by rotating a crank shaft of an engine using the high pressure.
In this case, since pressure in the cylinder is changed, torque generated from the crank shaft of the engine is not constant. In order to prevent a mismatch of the above-mentioned torque of the engine, an engine according to the related art has attempted to prevent the torque mismatch by mounting a fly wheel on the crank shaft to serve as inertia against a rotation.
The above-mentioned fly wheel is manufactured in a circular shape having a predetermined radius in order to uniformly maintain rotation force transferred from the crank shaft and to uniform a rotation speed.
According to the related art, Korean Patent No. 1148132 discloses an energy storage apparatus converting surplus power to store the converted surplus power as energy, the energy storage apparatus including a motor converting received electrical energy into mechanical energy; a fly wheel storing a rotation force generated by driving the motor; and a chamber receiving the fly wheel, wherein the fly wheel includes a rotating shaft having a first intaglio part formed on an outer peripheral surface thereof, a rotating body having a second intaglio part formed on an inner peripheral surface thereof, enclosing the outer peripheral surface of the rotating shaft and installed to be spaced apart from the rotating shaft, and a sliding hub inserted into the first and second intaglio parts and transferring the rotation force of the rotating shaft to the rotating body. However, according to the related art, the sliding hub decreases the rotation speed of the fly wheel and stores rotation energy of the fly wheel.
However, the fly wheel according to the related art is configured of a simple mass body and is rotated by the driving of the motor. In the case in which the driving of the motor is stopped, the fly wheel is rotated to a predetermined degree by inertia force and then stopped, such that it may not maintain the rotation force as much as possible.
In addition, since the fly wheel according to the related art is configured to have the sliding hub storing the rotation energy, the rotation energy of the fly wheel may be stored, but the rotation speed of the fly wheel may be decreased.
Therefore, the development of various fly wheels is demanded in order to solve the above-mentioned problems.